As part of its latest sero-survey conducted in the country’s commercial capital since the outbreak of the Covid-19 in March-April last year, the Brihanmumbai Municipal Corporation (BMC) said on Friday that Covid-19 anti-bodies were found in a sizeable 90.26 per cent of Mumbaikars who were either fully or partially vaccinated
In the fifth sero-surveillance study conducted by the BMC between August 12 and September 9, 2021, antibodies were found among the 79.86 per cent of unvaccinated citizens, while the prevalence of antibodies in people from slum as well as non-slum areas much higher compared to previous sero-surveys.
Disclosing the findings of the fifth sero survey, Mumbai Municipal Commissioner I S Chahal said here on Friday: “Even if antibodies are found, Mumbaikars will have to take precautions like use of masks, hand Hygiene and safe distancing norms”.
The BMC released the fifth sero- surveillance findings on a day when Mumbai recorded 387 infections and three deaths. As many as 434 Covid-19 patients were discharged from various hospitals after full recovery, the BMC pegged the total “active cases” in the metropolis at 4,658.
While the BMC had earlier conducted three Sero surveillance Studies for Covid-19 for all people, while it carried out one Sero-surveillance study only for Paediatric population previously. Anticipating the possible third wave of Covid-19, the fifth sero surveillance was conducted by the state public health department and LTMMC & GH, Sion Hospital with the support from A.T.E. Chandra Foundation and IDFC Institute.
The results of the previous three Sero-surveys conducted by M.C.G.M concluded that the recent trends in Sero-positivity corresponded with the Covid-19 cases in the second wave. The fifth Sero-survey could be instrumental in identifying trends of probable upcoming third wave and exposure of the population to the virus.
The study was cross-sectional in nature and included participants above 18 years of age, from all 24 wards of the city of Greater Mumbai. In all, 8,674 were samples were collected and tested. Anti-SARS-CoV2 lg G antibodies was detected using an ELISA based assay.
Study participants were selected by systematic random sampling and those visiting Municipal Dispensaries and General Practitioners' Clinics in slum and non-slum areas respectively. The participants were recruited with informed consent. Data collection was done by the means of a mobile software application.
According to the fifth serro-sero survey, overall Sero-prevalence in the city of Greater Mumbai was 86.64 period, while the study estimated around 87.02 per cent prevalenc in slums, while 86.22 per cent prevalence in non-slums in the 24 wards.
The sero-prevalence among males is 85.07%, sero-prevalence among females is 88.29 per cent which is higher as compared to males. Almost 65 per cent of those who participated in the study had received Covid-19 vaccines and 35 per cent did not receive any vaccine.
“Sero-prevalence amongst partially and fully vaccinated participants is 90.26 per cent. Sero-prevalence amongst those who have not taken Covid-19vaccine is 79.86 per cent,” Chahal said.
Of total samples, 20% were health care workers. Sero-prevalence in health care workers is 87.14%. The age-wise sero-prevalence varies from 80 per cent to 91 per cent among the study subjects.
“Overall sero-prevalence in slum and non-slum areas in the city of Greater Mumbai is much higher as compared to the last sero-survey. There is no statistically significant difference in sero-prevalence of Mumbai City and Suburbs. In this survey, sero-prevalence in slum population is 87.02 per cent, while in non-slum population it is 86.22 per cent which is a meagre difference,” Chahal said.
There is marginal difference in the gender-wise sero-prevalence with females showing 88.29% sero-prevalence as compared to males i.e., 85.07 per cent sero-prevalence was significantly higher in study subjects who received either first or both doses of Covid-19 vaccine as compared to their unvaccinated counterparts.
“The overall sero-positivity to the extent of 86% is based on qualitative test results and does not indicate protective levels of IgG antibodies. The study has recommended that people should continue to strictly follow the COVID Appropriate Behaviour (CAB),” Chahal said.